The present invention, subject of Disclosure Document No. 226238 Titled "CAPPER GAUGE FOR PRIMING SHELLS" which was Filed on May 8, 1989, relates to a portable hand-held manually activated controlled depth primer seating tool of a type employed by those engaged in reloading the cases of previously fired cartridges, and in particular for the insertion and precision seating of primers into center fire cartridge cases during the operations of reloading the same after firing. More specifically, for purposes of insuring consistency of cartridge ignition and thereby enhancing consistency of accuracy from round-to-round, the tool of instant invention is employed to seat primers to a known depth by precision measuring of primer and primer pocket variables of tolerance as well as the actual depth of primer insertion into the primer pocket in accomplishing seating, rather than by the heretofore so-called "feel" technique of primer seating as is that method generally employed in the use of most other primer seating tools. Also, it is to be understood that the tool subject hereof may be both satisfactorily and advantageously utilized for installing replacement primers to a measured depth of seating in center fire cartridge cases whether for rifle or pistol and whether of the rimmed or rimless type.
Among the marksmanship arts is that known as "precision" or "bench-rest" shooting, characterized by highly skilled and practiced individual employing finely tuned firearms and so-called "match" ammunition. The object of such marksmanship is basically the placement of all bullets through the same hole on the target at whatever range is being fired. In the accomplishment of such a marksmanship feat, the mechanical variables in firearm functioning and ballistic variables in ammunition performance must be reduced to minimum, and in the subject of this disclosure it is specifically the primer seating considerations attributable to reducing ballistic variables in ammunition performance to a minimum with which we are dealing.
Primer seating in cartridge reloading operations is typically accomplished with either a bench-mounted tool such as that taught by Lawrence in U.S. Pat. No. 3,313,201 dated Apr. 11, 1967, or a portable hand-held tool such as those respectively taught by either Schaenzer in U.S. Pat. No. 4,142,441 dated Mar. 6, 1979, and Lee in U.S. Pat. No. 4,222,305 dated Sep. 16, 1980, wherein all such tools regardless of either primer or primer pocket measurement and configuration variables compressively seat the primer to either a fixed depth as in the case of the Lawrence bench tool, or a depth of primer seating which "feels" right to the operator's sense of touch when tools such as those taught by Schaenzer and Lee are employed.
It is known that the level of sensitivity as well as reliability of primers is substantially effected by inconsistent and improper seating thereof, and certainly that the consistency of ignition of primers is directly related to the consistency of seating which in turn correlates to consistency of ignition of the cartridge main propellant charge and thereby the ballistic characteristic or a projected bullet and resultant consistency of accuracy delivered by a marksman and his firearm from round-to-round.
For purposes of discussion herein at present only, presume that all other variable firearm, shooter, environmental, and ammunition factors except primer seating are fixed and that we are dealing with primer seating variables only. In controlling primer seating variables there are two primary factors of importance under control of the reloader in gaining reliable consistency of primer ignition, and these are the proper orientation and positioning of the anvil head within the primer cup in relationship to the explosive compound held and retained therewithin so that when the firing pin strikes the primer all firing pin impact energy is expended in effecting detonation of an optimally sensitized explosive compound, which is accomplished when the head of the anvil is slightly pre-load compressed into the explosive compound so that optimum ignition sensitivity results from the compressive stresses set up therein, and the anvil head is neither removed from nor crushed into the explosive compound.
Reliable and consistent achievement of the proper orientation and positioning of the anvil head with respect to the explosive compound within a primer cap during the seating thereof within a center fire cartridge case primer pocket can only be repeatably accomplished by physically measuring and compensating for the primer variables, which is even true when the primer pocket has been previously reamed to both a uniform diameter and depth. The applicant herein by his invention provides a convenient new and novel tool as well as method for overcoming the problem of reloader non-uniformity in accomplishing the primer seating operation from cartridge-to-cartridge, and thereby eliminating the detrimental cartridge ignition and lack of accuracy consequences otherwise attributable thereto and consequent therefrom.